In construction, objects such as piles are often inserted into the earth. Such insertion may be by placement of a pile into an excavated hole, but it is typically quicker and more efficient to simply insert the pile into the earth without prior excavation. Such insertion may be by auguring the pile into the earth, crowding (forcing) the pile into the earth with constant pressure, applying a vibrational driving force to the pile, by striking the pile with repeated blows on an upper end of the pile, commonly referred to as hammering, or by combinations of those methods.
Another common construction task is to test the load bearing capacity of a pile that has been driven into the earth. In a particular, information obtained by striking a driven pile with a controlled striking force can be used to test and/or confirm the load bearing capacity of the driven pile.
The present invention relates to systems and methods for striking a pile for the purpose of driving the pile into the earth and/or testing a load capacity of a pile that has been driven into the earth. In the following discussion, the term “strike” will be used to refer to the act of impacting or applying a force to a pile for the purpose of driving the pile and/or for the purpose of testing the load bearing capacity of a driven pile.
Pile hammer systems typically employ a heavy ram member that is raised and allowed to fall such that the ram member repeatedly applies a short duration striking force directly or indirectly to the pile. A number of mechanisms are used to raise the ram member.
One type of pile hammer is commonly referred to as a diesel hammer. A diesel hammer injects diesel fuel below the falling ram such that the falling ram compresses and then ignites the diesel fuel as the ram applies the driving force to the pile. After the driving force has been applied to the pile, the ignited diesel fuel expands and forces the ram up to repeat the cycle.
Another type of pile hammer is commonly referred to as a hydraulic impact hammer. A hydraulic impact hammer uses a hydraulic actuator to raise the ram and force the ram down against the pile.
One type of pile hammer may be preferred over another depending on factors as the specifications of the pile to be struck, the purpose for applying the striking force to the pile (e.g., driving or load testing), and soil conditions. Often, it is desirable to change from one type of pile hammer to another type of pile hammer, sometimes for the same pile at the same location. For example, it may be desirable to use a diesel hammer to a certain soil depth and a hydraulic impact hammer beyond that depth, or vice versa. As another example, it may be desirable to use a diesel hammer to drive the pile to a predetermined depth and a hydraulic impact hammer to test the load bearing capacity of the pile at the predetermined depth.
The need exists for systems and methods that facilitate the change from one type of pile hammering to another type of pile hammering.